In a background elevator system, according to data received from a personal information terminal such as a mobile phone and representing a departure floor and a destination floor, a car operation is controlled, and audio guidance or the like is output to a user (see JP-A-2004-175519). Also, in a background elevator system, according to call registration information from a personal information terminal, changing of a assigned car is prohibited, and thus an assigned car cannot be changed, the exact assigned car is notified to a user (see JP-B-5457618).